Résumé

Investigation of the feasibility of supernovae as r-process sites using the r-process code r-Java

Zachary Shand (University of Calgary)

Mathew Kostka, University of Calgary
Rachid Ouyed, University of Calgary

The bulk of elements heavier than iron present in the universe today are understood to be a product of the r-process. The r-process occurs in a neutron rich environment where neutrons are rapidly captured by heavier nuclei to produce elements from iron up to uranium. This requires a high energy astrophysical event which is rich in free neutrons. Historically, supernovae have been the most promising location suspected of producing the heavy elements we see in our galaxy today; however, there are now competitive theories which take advantage of other high energy astrophysical events like neutron star mergers or quark novae. r-Java 2.0 is a state of the art nucleosynthesis code designed for investigation of the nuclear and astrophysical components of the r-process in a site independent way. Using the program, the effects of astrophysical environment and nuclear properties on the production of heavy elements in astrophysical environments like supernovae, neutron star mergers or quark novae can be studied. In particular, using r-Java it is possible to infer meaningful constraints on the ability of supernovae to produce heavy elements like gold or uranium and investigate how nuclear processes like beta-delayed neutron emission and fission may play a role in determining the elements produced during a supernova explosion. The results of simulating the r-process in supernovae show that in order to produce the heaviest of the r-process elements requires very specific hydrodynamic conditions to produce the initial conditions required for the production of heavy elements by the r-process. Comparison of these constrained initial conditions with explosion simulation models in literature suggest that supernovae are not the main source of heavy nuclear material in the galaxy.